Am I correct in assuming that the vacuum motor located in the upper right portion of the picture controls if the defroster works or not?
No, that’s the fresh air door. The shop manual shows the location and function of each of the vacuum motors in the HVAC system. You are not even in the right component.
Does anyone have photos of where it actually is on the heater box? Can you get ro kit by pulling out the radio?
Heater controls
Colors of the Vacuum line, Blue is the one you’re after…
Pretty sure you’re popping the dash pad
No need to touch the dash. It’s about center near the bottom of the dash. It’s not in the heater / condenser assembly. It’s in the fan box.
Is that the same layout for 68 & 69?
I don’t see dates anywhere in the chat
This is from my 1970, not sure how different it is, but you can see the bottom of the defrost vacuum canister. Directly above the silver canister mounted to the heater box, the bottom of it is the dark blue part. In my 70 you can get to it by removing the upper dash, and moving the passenger air ducting.
You might be able to get at it from below the dash, if it’s mounted similarly to mine you’d have a hell of a time replacing it from below.
Just in case you have a similar problem that I did, I recently dealt with it when I thought a new motor from WCCC was faulty. I forgot that the line going to the water valve was disconnected, which can make some doors not work since the control assembly will send vacuum to both, and if one is unplugged the other won’t work, so either plug the line or test all the airway doors with the temperature slider in both “Cool” and “Warm”.
It looks like if you take that panel off, the one where you have those lock nuts on the back you can get to with the glove compartment of & you have to remove the windshield wiper knob because the notch is too narrow
It’s the same one that you remove to remove the instrument cluster.
I’ll also check that water valve. Since the car no longer has AC, a lot of stuff has been capped off & disconnected.
What was especially confusing is that the ship manual said if the system malfunctioned, the defroster door would remain open all of the time because that’s the default.
When I got the car, the dealer said the defroster vacuum line simply fell off & they had to remove part of the dash to put it back. It worked for a while & then a small barely noticable vacuum leak appeared & no defroster.
This may well end up not being a total disaster.
The whole system works on vacuum. If the check valve is bad, or if the headlamps leak, or any other vacuum operated thing leaks, the defroster doesn’t work. Without a shop manual you have no hope of fixing it. It’s fairly complex.
Not to mention shortcuts taken by ignorant or dishonest shops, if previous owners took their cars to them. You may find things that didn’t follow the shop manual diagrams - or, parts a shop broke years ago, then simply left out when reassembling without telling anyone, as I did.
You may find everything totally in order, except for dried out vacuum plumbing. Not trying to be a jerk.
R.B.
He’s got a 1968. Completely different from later model Cougars. Doesn’t have that part in your photo.